#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>

void print_packet_pts_decoded_pts(AVFormatContext *pFormatCtx, int StreamIndex)
{
    printf("\n# PRINTING TIMESTAMPS OF ALL PACKETS & DECODED FRAMES \n\n");

    AVCodecContext* pCodecCtx = pFormatCtx->streams[StreamIndex]->codec;
    avcodec_open2(pCodecCtx, avcodec_find_decoder(pCodecCtx->codec_id), NULL);
    AVFrame *pFrameDecoded = avcodec_alloc_frame();
    AVPacket packet;

    int got_picture;

    while(!av_read_frame(pFormatCtx, &packet))
    {
        if(packet.stream_index == StreamIndex)
        {
            if(avcodec_decode_video2(pCodecCtx, pFrameDecoded, &got_picture, &packet) > 0)
            {
                if(got_picture)
                {
                    printf("  packet.pts=%lu => frame.pts=%lu\n", packet.pts, pFrameDecoded->pkt_pts);
                }
                else
                {
                    printf("  packet.pts=%lu => GOT NO PICTURE\n", packet.pts);
                }
            }
        }
        av_free_packet(&packet);
    }

//printf("\n# DECODING FRAMES FROM PACKET BUFFER...\n\n");

    AVPacket empty_packet;
    av_init_packet(&empty_packet);

    while(got_picture)
    {
        avcodec_decode_video2(pCodecCtx, pFrameDecoded, &got_picture, &empty_packet);

        if(got_picture)
        {
            printf("  USE EMPTY PACKET => frame.pts=%lu\n", pFrameDecoded->pkt_pts);
        }
        else
        {
            //printf("  DECODING DONE\n");
        }
    }

    av_free(pFrameDecoded);
    pCodecCtx = NULL;

    // go back to first packet/frame
    av_seek_frame(pFormatCtx, 0, 0, AVSEEK_FLAG_BACKWARD);
    avcodec_flush_buffers(pFormatCtx->streams[0]->codec);
}

int main(int argc, char *argv[])
{
    av_register_all();
    avcodec_register_all();

    AVFormatContext *pFormatCtx;

    // open file "10_frames_with_numberes.avi"
    if(avformat_open_input(&pFormatCtx, "10_frames_with_numberes.avi", NULL, NULL) == 0)
    {
        print_packet_pts_decoded_pts(pFormatCtx, 0);

        printf("\n# avformat_find_stream_info()\n");
        avformat_find_stream_info(pFormatCtx, NULL); // try to get info by decoding some frames

        print_packet_pts_decoded_pts(pFormatCtx, 0);
    }

    // close file
    if(pFormatCtx != NULL)
    {
        avformat_close_input(&pFormatCtx);
        pFormatCtx = NULL;
        printf("\n");
    }

    return 0;
}